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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

The effect of engine design characteristics on orbital transfer vehicle performance

The objective in maximizing performance for a space-based Orbital Transfer Vehicle (OTV) is to minimize the propellant required to successfully complete a given reference mission and thereby reduce launch and storage costs. Engine sizing studies were conducted which examined the effect of engine design characteristics on the total propellant required to accomplish the manned and unmanned OTV missions anticipated for the 1995 to 2010 time period. Two propellant combinations, O2/H2 and N2O4/MMH, were selected as baselines. Exotic combinations such as F2/H2 and O2/CH4 were also studied to identify potential benefits and growth capabilities. Parametric results showing the effects of engine thrust, number of engines, nozzle area ratio and payload requirements are presented for various reference missions. The results indicate that the optimum engine size and thrust are not significantly affected by detailed engine design characteristics.

Schmidt, G. R.↗
NASA NTRS1986

Cryogenic gear technology for an orbital transfer vehicle engine and tester design

Technology available for gears used in advanced Orbital Transfer Vehicle rocket engines and the design of a cryogenic adapted tester used for evaluating advanced gears are presented. The only high-speed, unlubricated gears currently in cryogenic service are used in the RL10 rocket engine turbomachinery. Advanced rocket engine gear systems experience operational load conditions and rotational speed that are beyond current experience levels. The work under this task consisted of a technology assessment and requirements definition followed by design of a self-contained portable cryogenic adapted gear test rig system.

Calandra, M.↗
NASA NTRS1988

Orbital transfer vehicle 3000 LBF thrust chamber assembly hot fire test program

The Aerojet Orbital Transfer Vehicle (OTV) Thrust Chamber Assembly (TCA) concept consists of a hydrogen cooled chamber, and annular injector, and an oxygen cooled centerbody. The hot fire testing of a heat sink version of the chamber with only the throat section using hydrogen cooling is documented. Hydraulic performance of the injector and cooled throat were verified by water flow testing prior to TCA assembly. The cooled throat was proof tested to 3000 psia to verify the integrity of the codeposited EF nickel-cobalt closeout. The first set of hot fire tests were conducted with a heat sink throat to obtain heat flux information. After demonstration of acceptable heat fluxes, the heat sink throat was replaced with the LH2 cooled throat section. Fourteen tests were conducted with a heat sink chamber and throat at chamber pressures of 85 to 359 psia. The injector face was modified at this time to add more face coolant flow. Ten tests were then conducted at chamber pressures of 197 to 620 psia. Actual heat fluxes at the higher chamber pressure range were 23 percent higher than the average of 10 Btu/in 2 predicted.

Schneider, Judy↗
NASA NTRS1989

Cryogenic fluid management technology requirements for the Space Transfer Vehicle

An in-house study was performed to design a cryogenic Space Transfer Vehicle (STV) for the late 1990s that can evolve with the demanding mission requirements of the manned exploration initiatives. An assessment of cryogenic fluid management technology issues associated with the STV was performed to identify technology gaps and propose advanced development activities.

Cramer, John M.↗
NASA NTRS1991

Space transfer vehicle concepts and requirements. Volume 1: Executive summary

The objectives of the Space Transfer Vehicle (STV) Concepts and Requirements studies were to provide sensitivity data on usage, economics, and technology associated with new space transportation systems. The study was structured to utilize data on the emerging launch vehicles, the latest mission scenarios, and Space Exploration Initiative (SEI) payload manifesting and schedules, to define a flexible, high performance, cost effective, evolutionary space transportation system for NASA. Initial activities were to support the MSFC effort in the preparation of inputs to the 90 Day Report to the National Space Council (NSC). With the results of this study establishing a point-of-departure for continuing the STV studies in 1990, additional options and mission architectures were defined. The continuing studies will update and expand the parametrics, assess new cargo and manned ETO vehicles, determine impacts on the redefined Phase 0 Space Station Freedom, and to develop a design that encompasses adequate configuration flexibility to ensure compliance with on-going NASA study recommendations with major system disconnects. In terms of general requirements, the objectives of the STV system and its mission profiles will address crew safety and mission success through a failure-tolerant and forgiving design approach. These objectives were addressed through the following: engine-out capability for all mission phases; built-in-test for vehicle health monitoring to allow testing of all critical functions such as, verification of lunar landing and ascent engines before initiating the landing sequence; critical subsystems will have multiple strings for redundancy plus adequate supplies of onboard spares for removal and replacement of failed items; crew radiation protection; and trajectories that optimize lunar and Mars performance and flyby abort capabilities.

Source record↗
NASA NTRS1990

Space transfer vehicle accommodations at transportation nodes

This task identifies requirements for accommodation of space transfer vehicles (STVs) at orbital transportation nodes. Requirements are based on mission models which include high energy missions and human exploration initiatives. Study data includes results of trade studies evaluating STV accommodations concepts at Space Station nodes and at alternative free-flying nodes. Data and scars on the Phase One Space Station Freedom to allow growth to the accommodation concepts are identified.

Hueter, Uwe↗
NASA NTRS1984

Multiple-pass trajectories for an aeroassisted orbital transfer vehicle

This paper investigates the use of multiple-pass trajectories for aeroassisted orbital transfer vehicles (AOTV) as a means of reducing the severe aeroheating environment and the extreme sensitivity to off-nominal trajectory and atmospheric conditions. One-, two-, and three-pass trajectories were calculated for AOTV's with ballistic coefficients ranging from 5 to 150 psf. Compared to the single-pass case, the maximum heat rate was reduced by 30 percent for two passes and 45 percent for three passes, while the maximum acceleration was reduced by 40 percent and 55 percent, respectively. The sensitivity of the trajectories to variations in atmospheric and orbital parameters was not significantly reduced.

Rehder, J. J.↗
NASA NTRS1985

Computational chemistry and aeroassisted orbital transfer vehicles

An analysis of the radiative heating phenomena encountered during a typical aeroassisted orbital transfer vehicle (AOTV) trajectory was made to determine the potential impact of computational chemistry on AOTV design technology. Both equilibrium and nonequilibrium radiation mechanisms were considered. This analysis showed that computational chemistry can be used to predict (1) radiative intensity factors and spectroscopic data; (2) the excitation rates of both atoms and molecules; (3) high-temperature reaction rate constants for metathesis and charge exchange reactions; (4) particle ionization and neutralization rates and cross sections; and (5) spectral line widths.

Cooper, D. M.↗
NASA NTRS1991

Space transfer vehicle concepts and requirements study. Volume 3, book 1: Program cost estimates

The Space Transfer Vehicle (STV) Concepts and Requirements Study cost estimate and program planning analysis is presented. The cost estimating technique used to support STV system, subsystem, and component cost analysis is a mixture of parametric cost estimating and selective cost analogy approaches. The parametric cost analysis is aimed at developing cost-effective aerobrake, crew module, tank module, and lander designs with the parametric cost estimates data. This is accomplished using cost as a design parameter in an iterative process with conceptual design input information. The parametric estimating approach segregates costs by major program life cycle phase (development, production, integration, and launch support). These phases are further broken out into major hardware subsystems, software functions, and tasks according to the STV preliminary program work breakdown structure (WBS). The WBS is defined to a low enough level of detail by the study team to highlight STV system cost drivers. This level of cost visibility provided the basis for cost sensitivity analysis against various design approaches aimed at achieving a cost-effective design. The cost approach, methodology, and rationale are described. A chronological record of the interim review material relating to cost analysis is included along with a brief summary of the study contract tasks accomplished during that period of review and the key conclusions or observations identified that relate to STV program cost estimates. The STV life cycle costs are estimated on the proprietary parametric cost model (PCM) with inputs organized by a project WBS. Preliminary life cycle schedules are also included.

Peffley, Al F.↗
NASA NTRS1994

The 7.5K lbf thrust engine preliminary design for Orbit Transfer Vehicle

This document summarizes the preliminary design of the Aerojet version of the Orbit Transfer Vehicle main engine. The concept of a 7500 lbf thrust LO2/GH2 engine using the dual expander cycle for optimum efficiency is validated through power balance and thermal calculations. The engine is capable of 10:1 throttling from a nominal 2000 psia to a 200 psia chamber pressure. Reservations are detailed on the feasibility of a tank head start, but the design incorporates low speed turbopumps to mitigate the problem. The mechanically separate high speed turbopumps use hydrostatic bearings to meet engine life requirements, and operate at sub-critical speed for better throttling ability. All components were successfully packaged in the restricted envelope set by the clearances for the extendible/retractable nozzle. Gimbal design uses an innovative primary and engine out gimbal system to meet the +/- 20 deg gimbal requirement. The hydrogen regenerator and LOX/GH2 heat exchanger uses the Aerojet platelet structures approach for a highly compact component design. The extendible/retractable nozzle assembly uses an electric motor driven jack-screw design and a one segment carbon-carbon or silicide coated columbium nozzle with an area ratio, when extended, of 1430:1. A reliability analysis and risk assessment concludes the report.

Hayden, Warren R.↗
NASA NTRS1988

Two designs for an orbital transfer vehicle: A comparison of two OTVs

The basic components of the design for the orbital transfer vehicle (OTV) are outlined. The Project Orion and the MOVERS OTV design are compared. The nature of the work and the specifics will be reviewed. The propellant systems are summarized along with the dollar savings. The strengths and weaknesses are highlighted for each OTV.

Source record↗
NASA NTRS1991

An automated rendezvous and capture system design concept for the cargo transfer vehicle and Space Station Freedom

A rendezvous sensor system concept was developed for the cargo transfer vehicle (CTV) to autonomously rendezvous with and be captured by Space Station Freedom (SSF). The development of requirements, the design of a unique Lockheed developed sensor concept to meet these requirements, and the system design to place this sensor on the CTV and rendezvous with the SSF are described .

Fuchs, Ron↗
NASA NTRS1991

Space transfer vehicle concepts and requirements study. Volume 2, book 4: Integrated advanced technology development

The Space Transfer Vehicle (STV) program provides both an opportunity and a requirement to increase our upper stage capabilities with the development and applications of new technologies. Issues such as man rating, space basing, reusability, and long lunar surface storage times drive the need for new technology developments and applications. In addition, satisfaction of mission requirements such as lunar cargo delivery capability and lunar landing either require new technology development or can be achieved in a more cost-effective manner with judicious applications of advanced technology. During the STV study, advanced technology development requirements and plans have been addressed by the Technology/Advanced Development Working Group composed of NASA and contractor representatives. This report discusses the results to date of this working group. The first section gives an overview of the technologies that have potential or required applications for the STV and identifies those technologies baselined for the STV. Figures are provided that list the technology categories and show the priority placed on those technology categories for either the space-based or ground-based options. The second section covers the plans and schedules for incorporating the technologies into the STV program.

Weber, Gary A.↗
NASA NTRS1993

Heating analysis for a Lunar Transfer Vehicle at near-equilibrium flow conditions

A heating analysis for a 15.2 m diameter Lunar Transfer Vehicle (LTV) at 0 and 10.6 deg angle of attack for a nominal trajectory through the earth's atmosphere is described. The analysis utilizes the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) with thin-layer, Navier-Stokes, thermochemical nonequilibrium options. Radiative heating levels are calculated using the Langley Optimized RAdiative Nonequilibrium (LORAN) and the Non-EQuilibrium AIr Radiation (NEQAIR) codes. At peak heating, the shock layer is substantially in equilibrium. Comprehensive spatial and spectral grid convergence studies have been implemented to quantify grid effects on the convective and radiative heating levels. Axisymmetric tests including the coupled effects of radiative energy transfer show negligible change to the convective heating and a 20 percent reduction in the radiative heating.

Gnoffo, Peter A.↗
NASA NTRS1985

Electron-impact vibrational excitation rates in the flow field of aeroassisted orbital transfer vehicles

This paper examines the vibrational excitation rate processes expected in the flow field of aeroassisted orbital transfer vehicles (AOTVs). An analysis of the multiple-quantum vibrational excitation processes by electron impact is made to predict the vibrational excitation cross sections, rate coefficients, and relaxation times which control vibrational temperature. The expression for the rate of electron-vibration energy transfer is derived by solving the system of master equations which account for the multiple-level transitions. The vibrational excitation coefficients, which are the prerequisite physical quantities in solving the obtained vibrational equation, are calculated based on the theoretically predicted cross sections. These cross sections are obtained from quantum mechanical calculations, based on the concept that vibrational excitation of molecules by electron impact occurs through formation of an intermediate negative ion state. Finally, the modified Landau-Teller-type rate equation, which is suitable for the numerical calculations for the AOTV flow fields, is suggested.

Lee, J.-H.↗
NASA NTRS1981

Orbital transfer vehicle - An overview

A summary is given of the concept definition phase of NASA's Orbital Transfer Vehicle (OTV) program. The mission requirements are threefold: (1) the ability to deliver payloads well beyond the capability of any current system at low acceleration levels, (2) the extension of the cost effectiveness from reusability and operational flexibility provided by the Shuttle at LEO to the geosynchronous altitude, and (3) the provision of the round trip capability needed to service and maintain this expanded and more valuable resource at GEO. The initial Shuttle-matched, reusable OTV is shown to be cost effective with low development cost, relatively short development period and high projected reliability. The performance enhancement provided by aero-assist is discussed, which will enable the difficult round trip to be flown in a single Shuttle launch. Two methods of reducing vehicle velocity are available: (1) aeromaneuvering, which uses vehicle lift to climb or descend and thereby correct for density variations, and (2) aerobraking which varies vehicle drag directly to correct for density.

Caluori, V. A.↗
NASA NTRS1983

Tanker orbit transfer vehicle and method

A method and apparatus for transportation between orbits are presented. A tanker orbit transfer vehicle includes two stages each of which includes a fuel container. The first stage may be left in an intermediate parking orbit while the second stage goes on to carry out a mission, thereafter to return to rendezvous and dock with the first stage. Fuel carried by the first stage may be utilized for travel of the two stages between the starting orbit and the parking orbit, and for return to the starting orbit. An aerobrake may be included in the system for use in the return to the initial orbit.

Ryan, G. G.↗
NASA NTRS1984

Lateral directional requirements for a low L/D aeromaneuvering orbital transfer vehicle

The lateral-directional aerodynamics and control requirements for a low L/D (0.3) aeromaneuvering orbital transfer vehicle are evaluated. A lateral directional RCS control concept that permits a linearized analysis is utilized to evaluate the effect of Dutch Roll frequency and damping on the atmospheric guidance and control performance. The bank rate and acceleration requirements for acceptable performance are defined and the sensitivity to a parameter similar to the lateral control departure parameter but involving the RCS jets is evaluated.

Gamble, J. D.↗